Rapid extraction and analysis of nonstructural carbohydrates in plant tissues.

Considerable time is necessary to determine the nonstructural carbohydrates (i.e., glucose, fructose, sucrose, starch) in plant tissues and some methods used for this purpose lack specificity. Two steps in such assays typically occupy much of the assay time: sample drying and homogenization/centrifugation. A laboratory method was therefore developed to carry out such assays without either of these stepsThe new method involved separation of the ethanol-soluble carbohydrates from disks or slices of plant tissue with hot aqueous ethanol and the in situ conversion of starch to glucose by enzymes. The amount of ethanol-soluble sugars and the glucose released from the tissue during the starch digestion were then determined in a microplate assay using an enzyme-coupled colorimetric reaction which was highly specific for glucose